This application is based upon and claims the benefit of priority from the prior Japanese Patent Application No. 2001-392673, filed Dec. 25, 2001, the entire contents of which are incorporated herein by reference.
1. Field of the Invention
The inventions relate to a disk drive in which information recorded on a disk medium is read by a head, and more particularly to a method and apparatus suitable for controlling access to a disk when a condensation sensor incorporated in the apparatus detects condensation.
2. Description of the Related Art
Hard disk drives (hereinafter referred to as xe2x80x9cHDDsxe2x80x9d) are known as representative disk drives in which information recorded on a disk medium is read by a head. The head is supported by an actuator that radially moves the head over the disk medium. Further, personal computers are known as representative hosts (host systems) that use HDDs. Most recent personal computers contain HDDs. Personal computers containing HDDs, in particular, notebook type personal computers of high portability, need to be prepared for both indoor and outdoor environments.
When using a personal computer containing an HDD outside, it is possible, for example, that the ambient temperature will abruptly change from high to low. In this case, condensation may occur within the HDD. If the HDD is used in this state, the HDD may malfunction.
In light of the above, Japanese Patent Application KOKAI Publication No. 10-320902 has proposed a technique (hereinafter referred to as xe2x80x9cprior artxe2x80x9d) for eliminating the problem that is raised when condensation occurs in HDDs. In the prior art, when a condensation sensor employed in an HDD has detected condensation, recording of data to a disk medium or reproduction of data from the disk medium is stopped. Further, the head is retracted to the ramp, and then the rotation of the disk medium is continued for a predetermined period of time. Thus, when the condensation sensor has detected condensation, the recording or reproduction of data is kept suspended until the condensation sensor detects no more condensation. Malfunction of the HDD is thus prevented.
In general, if the surface of the condensation sensor gets wet to the degree that enables detection of condensation, a lot of time is required until the condensation sensor is completely dry. Accordingly, in the prior art, once the condensation sensor detects condensation, recording or reproduction of data is suspended for a long time. However, it is possible that the surface of the head is already dry even if the surface of the condensation sensor is still wet. In this state, no problem occurs if recording or reproduction of data is executed, i.e., if the disk medium is accessed. In the prior art, however, even if the head surface is already dry, it is still regarded as wet until the condensation sensor itself is dry and detects no condensation. Thus, in the prior art, as long as the condensation sensor detects condensation, recording or reproduction of data is stopped even if the head is dry and can record or reproduce data.
The inventions have been developed in light of the above, and enable a head to promptly access a disk medium a predetermined period of time after a condensation sensor provided in a disk drive detects condensation, and before the condensation sensor itself is dry the prompt access to the disk medium being enabled by confirming, by a test reading operation, whether at least the surfaces of the head and disk medium are dry and the head can access the disk medium.
According to an aspect of the invention, there is provided a method of controlling access to a disk medium when a condensation sensor provided in a disk drive detects condensation, information recorded on the disk medium being read by a head in the disk drive. The method comprises: determining, from a detection result of the condensation sensor, whether condensation occurs in the disk drive; waiting for a predetermined period of time if it is determined that condensation occurs in the disk drive; executing a test reading operation on the disk medium after the predetermined period of time; and executing normal access to the disk medium if the test reading operation succeeds, when a host using the disk drive issues a request for the normal access to the disk medium.
Additional advantages of the claimed inventions will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objects and advantages of the invention may be realized and obtained by means of the instrumentalities and combinations particularly pointed out hereinafter.